Our major objective is to determine whether known single-locus genetic effects upon active- and passive-avoidance behavior are known single-locus genetic effects upon levels of biogenic amines in mouse brain are correlated. If such correlations are found, genetic analyses will be conducted to determine whether behavioral responses and neuroendocrine events are controlled by the same loci and thereby represent possible pathways by which genes influence behavior. Behavioral variation will be assessed using active- and passive-avoidance testing procedures which have been demonstrated to be reliable in this Laboratory. Genetic techniques will include the use of "Mendelian models" as well as a new recombinant-inbred strain technique. A combination of techniques employing simultaneous determination of the activity levels of the three major amines, norepinephrine, serotonin, and dopamine, and their respective turnover rates will be used. These techniques recently have been used and modified in our laboratory to be usable with small brain (mouse) samples. Our primary interest is in the interrelationships of environmental, genetic, and neurochemical factors in the determination of behavior.